diff --git a/packages/element-templates-json-schema/src/defs/properties.json b/packages/element-templates-json-schema/src/defs/properties.json
index 20f9d12..c3e049f 100644
--- a/packages/element-templates-json-schema/src/defs/properties.json
+++ b/packages/element-templates-json-schema/src/defs/properties.json
@@ -88,7 +88,23 @@
                   }
                 },
                 {
-                  "required": ["scriptFormat"]
+                  "required": [
+                    "scriptFormat"
+                  ]
+                },
+                {
+                  "allOf": [
+                    {
+                      "not": {
+                        "required": ["implementationType"]
+                      }
+                    },
+                    {
+                      "not": {
+                        "required": ["scriptFormat"]
+                      }
+                    }
+                  ]
                 }
               ]
             }